Package de.saar.chorus.domgraph.codec.basic

Class Chain

java.lang.Object

de.saar.chorus.domgraph.codec.InputCodec

de.saar.chorus.domgraph.codec.basic.Chain

public class Chain
extends InputCodec

An input codec that generates pure chains. Pure chains are normal dominance graphs in which upper and lower fragments alternate in a zig-zag shape (see e.g. Koller's Ph.D. thesis, Chapter 6.4). They correspond to the predicate-argument structure of (possibly nested) NPs and (possibly transitive) verbs, and as such are a convenient type of graphs for benchmarks.

Author:

Alexander Koller

Field Summary

Fields

Modifier and Type	Field	Description
static int	ERROR_CHAIN_LENGTH

Constructor Summary

Constructors

Constructor	Description
Chain()

Method Summary

Modifier and Type	Method	Description
void	decode(Reader inputStream, DomGraph graph, NodeLabels labels)	Reads an USR representation from a Reader.
Reader	getReaderForSpecification(String spec)	Determines a Reader from which the USR specified by the spec will be read.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Details

ERROR_CHAIN_LENGTH

public static int ERROR_CHAIN_LENGTH

Constructor Details

Chain

public Chain()

Method Details

decode

public void decode(Reader inputStream,
 DomGraph graph,
 NodeLabels labels)
            throws IOException,
ParserException,
MalformedDomgraphException

Description copied from class: InputCodec

Reads an USR representation from a Reader. This method converts the USR into an equivalent labelled dominance graph and stores this graph in a DomGraph and the labels in a NodeLabels object. You must implement this method in every concrete input codec.

The graph and labels objects passed to this method need not be empty; it is the responsibility of this method to clear them first.

Specified by:

decode in class InputCodec

Parameters:

inputStream - the reader from which the USR is read

graph - the dominance graph into which the USR is converted

labels - the node labels of the labelled dominance graph

Throws:

IOException - if an I/O error occurred while reading from reader

ParserException - if a syntactic error occurred while parsing the USR

MalformedDomgraphException - if a semantic error occurred, i.e. the USR cannot be converted into a dominance graph

getReaderForSpecification

public Reader getReaderForSpecification(String spec)

Determines a Reader from which the USR specified by the spec will be read. In the context of the Chain input codec, the spec must be a string representing a number, which is taken to specify the length of the chain to generate. (This is different than the implementation in InputCodec, where spec is read as a filename.)

Overrides:

getReaderForSpecification in class InputCodec

Parameters:

spec - a string specifying the length of the chain

Returns:

a StringReader for the given string